Oyster processing method

ABSTRACT

A declustering component breaks clusters of oysters into individual oysters and an opening component separates oyster half shells thereby exposing the meat of the oysters. The declustering component includes a rotatable drum having a feed opening for oyster clusters and slots which permit only single oysters to leave the drum. The opening component includes mechanical means for disconnecting the oyster half shells by applying opposed shearing forces adjacent to the shell joint.

This is a division of application Ser. No. 773,187 filed Mar. 1, 1977now U.S. Pat. No. 4,143,444.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to apparatus for declustering and openingbivalves and the opening method.

2. Prior Art

Several United States patents disclose mechanical apparatus forprocessing bivalves which may or may not be first subjected to heattreatment. Oyster tumbling apparatus is shown in the following patents,but not for the purpose of breaking up clusters of oysters.

    ______________________________________                                        Seal et al.    2,823,414                                                      Lapeyre et al. 3,007,801                                                      Lapeyre et al. 3,037,237                                                      Jurisich       3,238,560                                                      ______________________________________                                    

Also the following patents apply a shearing force to the two oyster halfshells.

    ______________________________________                                        Plock          2,473,609                                                      Gaelti et al.  2,738,546                                                      Matzer et al.  3,203,034                                                      Lapeyre et al. 3,239,877                                                      ______________________________________                                    

SUMMARY OF THE INVENTION

An object of the present invention is to provide oyster-processingapparatus which can be adjusted to accommodate various species ofoysters.

Another object is to provide oyster-processing apparatus which willprocess oysters with minimum mutilation of the meat of the oysters.

It is also an object to provide oyster-processing apparatus which isadaptable to assembly line use.

The foregoing objects can be accomplished by providing an openingcomponent including mechanical means for applying opposing forces toclosed oyster half shells, thereby shearing the half shells apart.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective of one possible layout of oyster processingapparatus in accordance with the present invention.

FIG. 2 is a side elevation and FIG. 3 an end elevation of a declusteringdrum in accordance with the present invention, each figure having partsshown in section and parts broken away.

FIG. 4 is a fragmentary side elevation of a modified declustering drumincluding a dislodging cage and FIG. 5 is a fragmentary section taken online 5--5 of FIG. 4.

FIGS. 6 and 7 are fragmentary end elevations of modified declusteringdrums including other dislodging means.

FIG. 8 is a fragmentary section taken on line 8--8 of FIG. 7, FIG. 9 isa fragmentary section taken on line 9--9 of FIG. 7, and FIG. 10 is afragmentary section taken on line 10--10 of FIG. 8.

FIG. 11 is a top perspective of an opening component in accordance withthe present invention, and FIG. 12 is a fragmentary top perspective of aportion of the component shown in FIG. 11 with parts broken away. FIG.13 is an end elevation and FIG. 14 is a longitudinal section of theopening component of FIG. 11. FIGS. 15, 16 and 17 are fragmentarylongitudinal sections of the opening component of FIG. 11 in progressivestages of operation.

FIGS. 18, 19 and 20 are fragmentary longitudinal sections of the openingcomponent of FIG. 11 modified to open oysters in body-down orientation,the separate figures illustrating progressive stages of operation.

FIG. 21 is a longitudinal section of another modified opening component.FIGS. 22, 23 and 24 are fragmentary longitudina sections of the openingcomponent of FIG. 21 in progressive stages of operation.

FIG. 25 is a longitudinal section of still another modified openingcomponent and FIG. 26 is a section taken on line 26--26 of FIG. 25. FIG.27 is a fragmentary elevation of the opening component of FIG. 25.

FIG. 28 is a fragmentary longitudinal section of the opening componentof FIG. 25 further modified to open oysters in body-down orientation.

DETAILED DESCRIPTION

The outer part of an oyster consists of two half shells, one much morerounded and cuplike than the other. The more cuplike half shell will bereferred to as the "body". The other half shell, which is relativelyflat, will be referred to as the "lid".

The present invention can be used to process different species ofoysters with only minor adjustments to accommodate for the difference insize of the various species. One possible assembly of the necessarycomponents is shown in FIG. 1. Any suitable means can be provided totransport clusters of oysters to a hopper 1. Such means can include astandard belt conveyor 2. Oyster clusters travel through the hopper intoa declustering drum 3 and nozzles 4 shower the clusters with water orsolvent. Such water or solvent is collected in a pan 5 and discharged bya pipe 6 for disposal or for recycling through the nozzles.

The declustering drum 3 is rotatable to tumble oyster clusters againsteach other and to drop the clusters onto impact members for breaking upthe oyster clusters. The impact members can be rods or bars extendinglongitudinally or transversely inside the drum. Alternatively, suchmembers can be spike-shaped objects with their sharp points protrudinginside the drum. Another alternative is to shape the drum itself in sucha way that the inner circumference of the drum includes abrupt cornersor bends. The impact members should present an impact surface area largeenough to prevent breaking individual oysters, yet small enough tofacilitate the declustering process. Separated single oysters fall fromthe drum through a slot large enough to allow single oysters to leavethe drum yet small enough to retain clusters of oysters inside the drum.

As the drum rotates, oyster clusters on the inside of the drum will betumbled against each other and against the impact members. Clusters willbe broken into groups of fewer and fewer oysters and single oysters willbe broken off the clusters and drop through the slot or slots in thedrum. Naturally, any motion of the drum which will promote declusteringand the passage of single oysters through the drum slots could besubstituted for the rotary motion.

The declustering component shown in FIGS. 2 and 3 includes a base 7supporting a motor 8. The armature shaft of the motor extends into atorque-adjusting gearbox 9. A motor pulley 10 is secured to the drivengear shaft 11 extending from the gearbox. Rotary power transferred fromthe motor through the gearbox to the motor pulley 10 is transmitted to adrum pulley 12 by belts 13. Such drum pulley is carried by a drum axle14 which extends through a bearing in base 7 and is inclined upwardlyfrom it.

The drum includes a collar 15 located at the center of a disk-shapedendpiece 16. A supporting cone 17 has its base attached to such endpieceby bolts 18. The drum axle 14 extends through collar 15 and through ahole in the tip of the supporting cone. The supporting cone and theendpiece are secured to the drum axle by a nut 19 screwed onto thethreaded upper end portion of the axle. A ring-shaped endpiece 20 isconnected to endpiece 16 by circumferentially spaced, transverselyadjustable rods 21 and alternately arranged nonadjustable rods 22.

Oyster clusters can be fed into the drum through opening 23 of theendpiece ring 20, and the drum is inclined downwardly from such openingto facilitate retention of the clusters in the drum. One end of eachnonadjustable rod 22 is firmly attached to the lower endpiece 16 and theother end of such rod is firmly attached to the upper endpiece 20. Eachend of each adjustable rod 21 is attached to a separate mounting bracket24 adjustable radially of an endpiece. As best seen in FIG. 3, eachmounting bracket has a radial slot 25 through which a securing pincarried by an endpiece extends. Such pins preferably are bolts 26, asshown in FIGS. 2 and 3, which attach the brackets to the drum endpieces.

By sliding the brackets 24 radially in or out relative to bolts 26, thedistance between an adjustable rod 21 and the adjacent nonadjustablerods 22--represented by the letter A in FIG. 3--can be increased ordecreased. Such distance should be adjusted to be large enough to enablesingle oysters to fall between adjacent rods, as shown at the bottom ofFIG. 3, yet small enough to retain clusters of oysters within the drum.In addition to defining the declustering drum slots, the rods serve asimpact members presenting blunt yet small impact surface areas toclusters of oysters tumbled in the drum.

Because oyster clusters are irregular in shape, a cluster can becomelodged in a declustering drum slot, as shown in the left portions ofFIGS. 5, 6 and 7. Different means for dislodging such clusters are shownin FIGS. 4 and 5, FIG. 6, and FIGS. 7 to 10.

The dislodging means shown in FIGS. 4 and 5 includes a rotatable cagemounted above the declustering drum. An arm 27 extending upwardly frombase 7 carries a sleeve 28 on its upper end. An upper axle 29 extendsthrough the sleeve inclined substantially parallel to the drum axle 14.The upper portion of the upper axle carries the disloding case whichincludes star-shaped endpieces 30 and 31 having radial arms 32 connectedby dislodging rods 33. Each endpiece has a central aperture, and acentral spacer sleeve 34 extends between the central portions of theendpieces. The upper axle extends through the apertures of the endpiecesand the central sleeve. A nut 35, on the upper end portion of the axle,secures the dislodging cage on the axle. The lower end portion of theupper axle carries an upper pulley 36.

It is desirable that the dislodging cage rotate in the directionopposite the direction of rotation of the declustering drum. For thisreason, a second gearbox 37 is provided which houses reversing gearing38 driving a pulley 39. As best seen in FIG. 4, the rotating powertransmitted from themotor to the drum pulley 12 is further transmittedto reversing gearing 38, to pulley 39, and then to the upper pulley 36by a belt 40.

As indicated by the arrows in FIG. 5, if the declustering drum rotatesclockwise, the dislodging cage will rotate counterclockwise. Thedislodging rods 33 will move into and out of the spaces between thedeclustering drum rods 21 and 22 much like gear teeth mesh with thegrooves of a companion gear, thereby dislodging any oyster clustersstuck in such spaces. It would be possible to eliminate the means usedto rotate the dislodging cage and rely instead on the gearlike action ofthe declustering drum rods and the dislodging cage star arms 32 torotate the dislodging cage.

In the modified dislodging means shown in FIG. 6, an arm 4 extendsupwardly from the base 7, on which arm is mounted a pair of fluidpressure jacks 42 and an actuating switch 43. Dislodging rods 44 extendparallel to the declustering drum rods and are attached to plunger arms45 extending downwardly from the respective jacks 42. The switch islocated so that, as the declustering drum rotates, each adjustable rod21 triggers closing of the switch. Triggering of the switch causes bothplunger arms 45 to be projected downward at opposite sides of thetriggering rod, thrusting the arms and the dislodging rods into thedeclustering drum between the triggering rod 21 and the two fixed rodson opposite sides of such rod 21. Oyster clusters caught between thedeclustering rods will be struck by the rods 44 and dislodged.

The modified dislodging means shown in FIGS. 7 through 10 requires amounting for the declustering drum adjustable rods different from thatin the two previously discussed disloding means. In this arrangement theadjustable rods 21' serve as dislodging rods which are movable towardthe inside of the declustering drum. As best seen in FIG. 9, eachadjustable rod 21' extends a short distance through the outer end of anL-shaped mounting bar 46. The bar extends perpendicular to the axis ofthe rod toward the center of a drum endpiece 16 or 20 and through a slot47 of a mounting box 48. The sides of the mounting box abut the drumendpiece except for the slot defined above. As shown in FIG. 10, the boxis secured to the endpiece by bolts 49.

A threaded adjusting screw 50 having a head at each end extends fromoutside the bottom of the mounting box, through a tapped hole in the boxbottom and through an untapped hole 51 in that portion of L-shaped bar46 perpendicular to the drum endpiece. The latter hole is of a sizesufficient to permit the bar to slide longitudinally of the pin. The baris held away from the bottom of the mounting box and normally tightagainst the upper head of the adjusting pin by a compression spring 52.The distance between an adjustable rod 21' and the adjacentnonadjustable rods 22, labeled A in FIG. 9, can be adjusted by turningthe adjusting screw to cause more or less of it to extend inside themounting box.

As shown in FIG. 8, the upper end of an arm 27' extending upwardly frombase 7 carries a sleeve 53. A wheel 54 is attached to the arm 27' by ashort axle 55 extending through such sleeve. The size of the wheel ischosen so that, as the declustering drum rotates, the rim of the wheelwill engage the end portions of the adjustable rods 21'. Each L-shapedbar 46 will be forced downward, compressing spring 52 and thrusting theadjustable rod 21' toward the center of the declustering drum. Theadjustable rods are shown in downwardly thrust positions in FIGS. 7, 8and 10. This movement will dislodge any oyster cluster stuck between thedrum rods as they pass wheel 54.

The single oyster which have dropped through slots of the declusteringdrum can next be graded according to ranges of size. This can be done bya machine such as the vibrating grader 56 shown in FIG. 1, or by hand.It is desirable that the oysters be size-graded before they aretransported to the opening components 57 so that each opening componentoperates on oysters of roughly the same size.

In the opening component shown in FIGS. 11 to 17, a conveyor belt 58 issupported by a conveyor frame which includes legs 59, longitudinal sideplates 60 at opposite sides of the conveyor belt, longitudinalbelt-supporting members 61 beneath the belt, crossbars 62 connectingmembers 61, belt height adjusting bolts 63 and adjusting bolt attachinglugs 64. Front flights 65 and rear flights 66 are secured to theconveyor belt by bolts 67 and 68, respectively. The top of each frontflight is inclined upwardly in the direction the conveyor travels, andthe leading edge 69 of each front flight is undercut to trap an oysterplaced ahead of such flight. When viewed from above, the leading edge ofthe flight 65 is V-shaped with the sides of the V flared forward fromthe center of the belt to the outer edes of the belt in the directionthe conveyor travels. The rear flight 66 is shown as a length of angleiron including a horizontal flange secured to the conveyor belt and aflange upstanding from the belt.

Mounted on the conveyor frame adjacent to opposite edges to the belt aretwo hydraulic jacks 70 including upwardly-extending plungers 71. A crossmember 72 is mounted on the jack plungers by sleeves 73 carryingopposite ends of the cross member. Each sleeve encircles a jack plungerand is secured to such plunger by a set screw 74. A concussion bridgebarrier 75 is secured to the cross member by bolts 76 extending throughspaced parallel vertical slots 77 and screwed into tapped holes in thecross member. In this arrangement the concussion barrier extendstransversely of the conveyor belt and above it. When the jack plungersare at rest in their lower positions, the distance from the bottom ofthe concussion barrier to the conveyor belt will be determined by theposition of the bolts 76 in the slots 77.

Another feature of the opening component shown in FIGS. 11 to 16 is theassembly for triggering upward projection of the jack plungers 71 toraise barrier 75. A switch 78 and transversely spaced control rodmounting brackets 79 are attached to the downstream side of theconcussion barrier with reference to the direction of movement ofconveyor belt 58. As best seen in FIG. 14, the switch includes adownwardly projecting button 80 and rod support lugs 81 also projectingdownward. Returning to FIG. 11, a turnable control rod 82 extendssubstantially horizontally through holes in the mounting brackets 79 andlugs 81. An activating tongue 83 is attached to the control rod andprojects upstream from it so that turning of the rod 82 will swing thetongue to actuate switch 78. The swinging end portion of the tongue isdirectly under the switch button.

Control rod 82 has end portions 84 bent at right angles to itstransverse central portion so as to extend upstream. One such endportion projects past each end of the concussion barrier 75. A sensorbar 85 extending transversely of belt 58 ahead of the barrier has oneend carried by one control rod end portion and the other end carried bythe other control rod end portion. The upstream margin of the sensor baris curved upward to facilitate entry of an oyster under it. When thetriggering assembly is at rest in its lower position the sensor bar islocated at a height above the conveyor belt so as to be in the path ofthe upper portion of an oyster carried on belt 58.

Progressive stages in the operation of the opening component areillustrated in FIGS. 15, 16 and 17. An oyster 86 is placed on thedownstream side of a front flight 65 of belt 58, preferably lid down,with the oyster abutting the leading edge of such flight. The V-shapedidentation in the flight leading edge holds the oyster in the center ofthe belt. Since the upper surface of the front flight is inclinedrearward and downwardly, the height of the leading edge varies from aminimum at the center of the conveyor to a maximum at the sides of theconveyor. Such minimum and maximum heights can be chosen so that the lidof an oyster placed ahead of a front flight will be engaged by the frontflight leading edge at approximately the joint between the oyster halfshells. The lid of an oyster slightly larger than the average size ofoysters to be opened will be engaged farther from the center of theflight where the leading edge is higher. The lid of an oyster slightlysmaller than average will be engaged at locations closer to the centerof the flight where the flight leading edge is lower.

The oyster is transported toward concussion bridge barrier 75 by theflight 65 to contact sensor bar 85. As best seen in FIG. 15, the sensorbar will be wedged upward by the forwardly-moving oyster to swing theswitch-actuating tongue 83 upward. Such tongue will reciprocte theswitch button 80, thereby triggering upward projection of the jackplungers 71. The height of the concussion bridge barriers 75 has beenadjusted by the slots 77 and bolts 76 so that the bottom edge of thebarrier plate is struck forcibly by the portion of the leading side ofthe upper oyster shell just above the joint between the lid and body,which arrests forward movement of the upper shell. As the oyster isboxed between the leading edge of the front flight 65 and the concussionbridge barrier 75, the moving flight applies a downstream force on theoyster lid 88 while the concussion bridge barrier applies an upstreamreaction force on the arrested shell body 87 so that the oyster halfshells are subjected to an abrupt, strong shearing jolt whichdisconnects or parts the shell parts and shell-holding muscles. Thedisconnected body 87 and lid 88 are shown in FIG. 16.

At this instant, the jack plungers are in the process of being projectedupwardly by the jacks so that the concussion bridge barrier 75 is beingmoved upward. The barrier is still low enough, however, so that itcontinues to engage the body shell 87 as shown in FIG. 16. The separatedbody slides down the rearwardly inclined top of the front flight 65 bycontinuing travel of the conveyor. As shown in FIG. 17, eventually rearflight 66 will engage the body and transport it downstream away from theconcussion plate while the lid continues to be moved by the front flight65.

The concussion bridge barrier 75a shown in FIG. 12 has a concave bottomof a shape roughly corresponding to the shape of an oyster body so thatthe reaction force will be exerted on the body over a substantial arearather than only at one point. The sensor bar 85 used with such abarrier could also be concave upward.

Instead of the oysters being placed on the conveyor their bodies up, asdescribed and shown in FIGS. 14 to 17, the opening component couldoperate with the oyster lids up and bodies down. In such case, as bestseen in FIGS. 18, 19 and 20, the front flight 65 would have a higherleading edge and the concussion bridge barrier 75 would be adjustedupward relative to the cross member 72 by adjusting the vertical slotsand bolts 76 to assure that the opposed shearing forces would be exertedon the oyster as close as possible to the joint between the lid andbody. Similar adjustments can be made for different sizes and species ofoysters.

The modified opening component shown in FIGS. 21 to 24 uses a standardchain conveyor including two parallel endless transporting chains. Theoyster-carrying apparatus includes a flexible tray or reaction member 89bridging between two flights 90 and 91, each of which flights bridgesbetween and is carried by the transporting chains. The upstream flight90 is shaped similarly to the front flight 65 of FIG. 11, except thatflight 90 has an upwardly extending flange 90' on its trailing edgecorresponding to the angle rear flight 66 in FIG. 11. The downstreamflight 91 includes an upstream edge 93 which is V-shaped in plan andflared in the upstream direction. In FIG. 21, an oyster 86 is shown asbeing supported lid down by tray 89 between the two flights 90 and 91.Both the leading edge of flight 90 and the upstream edge 93 of flight 91engage the oyster approximately at the joint between the lid and body,edge 93 being held against the oyster by a compression spring 92anchored against a flange 91' of flight 91.

As in the previously described embodiment, this opening componentincludes a pair of hydraulic jacks mounted at opposite sides of theconveyor with a cross member 72' extending between and carried by thejack plungers. Such cross member is secured to the plungers by sleevesand set screws as described in connection with FIG. 11. A concussionbridge barrier 75' is adjustably mounted on the cross member by boltsextending through vertical slots in the barrier as also described inconnection with FIG. 11. In this component the barrier is secured to thedownstream side of the cross member and has a right angle bend 94directed upstream to form an impact edge 95. Such impact edge isV-shaped and flared in the upstream direction in plan.

Brackets 97, extending upstream from the outer end portions of crossmember 72', carry a downstream axle 98 which in turn carries adownstream pulley 99 over the center of the conveyor. An upstream pulley100 is mounted to enable it to rise and fall relative to the conveyor. Amounting frame for the upstream pulley includes: two upwardly extendingframe supports 101 adjacent to opposite sides of the conveyor; a crossmember 102 connecting the upper portions of the supports; a shaft 103extending between the support upper portions below the cross member; andtwo hanger arms 104 depending from the shaft, one on each side ofupstream pulley 100. The outer ends of an upstream axle 105, carryingthe upstream pulley at its center, extend through vertical slots 106 inthe hanger arms. Each end of the axle has a cap 107 preventing an axleend from being pulled out of an arm slot.

In this arrangement, the upstream axle 105 can move vertically in theslots 106 so that the upstream pulley is also free to move vertically.The spacing between the upstream and downstream axles is fixed by spacerbars 108. In addition, two rods 109, connected to axle caps 107, extendupward through brackets 110 attached to the hanger arms 104. The upperend of each rod is capped above its bracket 110. Compression springs 111encircling rods 109 have their opposite ends bearing against the axlecaps 107 and the brackets 110 to bias the upstream pulley downward. abelt 112 connects the pulleys 99 and 100. As best seen in FIG. 21, achain and sprocket drive drives belt 112 in synchronism with the chainconveyor carrying flights 90 and 91.

Progressive steps in the operation of this oyster opening component areillustrated in FIGS. 22, 23 and 24. The upper shell of an oyster 86 iscarried by the tray 89 to engage belt 112. The oyster moves under theupstream pulley 100, wedging the pulley upward in opposition to springs111, and moving rods 109 upward relative to the brackets 110. The weightof the pulley supporting assembly as well as springs 111 press theoyster against tray 89. A triggering assembly including an activatingtongue 83', attached to the upper portion of one of the rods 109, throwsa switch 88' to start a time delay for energizing the hydraulic jacks tobegin the upward projection of the jack plungers 71. The held-downoyster will next strike the impact edge 95 of the concussion bridgebarrier before it begins its upward movement. Just after the oysterstrikes the barrier the jacks are actuated to release the downwardpressure exerted by the belt on the oyster and to lift the barrier abovethe oyster. As shown in FIG. 24, the oyster body 87 is separated fromthe oyster lid 88 by the shearing jolt. The body slides down theinclined upper surface of the upstream flight 90 until engaged by theupwardly extending flange 90' by which such body will be carrieddownstream away from the opening component. The flange is preferablylocated on flight 90 a distance less than the diameter of an oyster fromthe flight leading edge so that the oyster meat, which normally remainsin the oyster body portion, is not dragged across the sharp trailingedge of the oyster lid.

The modified opening component shown in FIGS. 25 to 27 also uses adouble chain conveyor to transport oysters to be opened. Anoyster-carrying flight 113 bridges and is carried by the conveyorchains. The flight includes a horizontal tray portion 115 and ajoint-engaging leading edge 116. In this embodiment, the leading edge116 is not V-shaped, but instead includes short teeth 117, best seen inFIG. 26, extending from edge 116 in a downstream direction. The flightalso includes a trailing flange 118 which performs the same functions asthe rear flight 66 of FIG. 11 and the flange 90' of FIG. 21. Cam liftramps 119 and down ramps 120, formed as part of flight 113, are locatedover the conveyor chain.

Mounted on each side of the conveyor frame are two upwardly extendingsupporting columns 121 carrying upwardly extending sleeves 122. Thesleeves are adjustably secured to the columns by set pins 123.Belt-supporting frame members 124 extend longitudinally of the conveyorover sleeves 122. The upstream portion of each frame member is attachedto an upstream sleeve by a hinge 125. The middle portion of such framemember is secured to a downstream sleeve by a pin 126 carried by a shaft127 in the downstream sleeve. Pin 126 extends upward from the downstreamsleeve through holes in the lower and upper sides of the frame memberand ends above the frame member in a cap and washer 128. A compressionspring 129 encircles the upper portion of pin 126 and biases the framemember downward. The downstream portion of each frame member carries alongitudinal sleeve 130. The position of the sleeve on the frame membercan be adjusted by a threaded pin 131 extending through a tapped bracket132 on the frame member and a tapped bracket 133 on the sleeve.

Axle brackets 134 are mounted on the upper sides of the upstream endportions of frame members 124 and on the upper sides of the downstreamend portions of longitudinal sleeves 130. Upper axles 135 extendtransversely of the conveyor between the axle brackets. A lower axle 136extends between arms 137 extending downward from the longitudinalsleeves. As best seen in FIG. 26, lower axle 136 and upper axles 135each carry two pulleys with one pulley offset a short distance from anaxle center and the other pulley offset an equal distance to the otherside of the axle center. Two endless belts 138 connect the pulleys.

The inner side of each longitudinal sleeve 130 includes a longitudinaladjustment bar 139 supporting the concussion bridge barrier assemblywhich includes channel flanges 140 slidable along the length of the bar,support sleeve 141 extending downward from the flanges and receivingbridge barrier support arms 142, to which are attached the outward endportions of a horizontal concussion bridge barrier 75". Cam followers inthe form of small wheels 143 extend downward from the outward ends ofthe concussion bridge barrier and are disposed above the conveyor chainsin alignment with cam ramps 119 and 120.

The operation of this opening component is quite similar to theoperation of the components previously described, the major differencebeing that in this component the lifting action of the bridge barrier isachieved by cam ramps rather than by hydraulic jacks. Flight 113carrying an oyster 86 approaches the bridge barrier and the upper oysterhalf shell first engages belts 138. Such belts press he oyster againstthe oyster-carrying apparatus due to the weight of their supportingframe and the force of spring 129. Nevertheless, as the oyster is wedgedunder the belts the entire supporting frame is forced upward. Concussionbarrier 75" is positioned a set distance below belts 138 and is strucksharply by the upper half shell of the held-down oyster. Shortly afterthe shearing jolt cam follower wheels 143 engage the cam lift ramps 119forcing the barrier upward to clear the oyster. The shearing jolt willseparate the lid from the body and the body will slide down the inclinedupper surface of flight 113. Flange 118 upstanding from flight 113carries the body downstream away from the opening component.

As best seen in FIG. 27, if the shearing jolt exerted on the oyster halfshells is not sufficient to disconnect the lid and body, the raising ofthe bridge barrier will still enable the unopened oyster to pass beneaththe barrier. In the same installation it may be desirable to provide twoopeningcomponents in series on the same conveyor frame so that oystersnot opened by impact with the first bridge barrier would be opened byimpact with a second bridge barrier. Alternatively, unopened oysters cansimply be run through the same opening component again. Anotheralternative is to provide a second opening component adjusted to opensmaller oysters so that oysters not opened by impact with the firstbridge barrier would strike the second bridge barrier nearer the jointbetween the oyster half shells.

FIG. 28 shows one way the opening component of FIGS. 25 to 27 can bemodified to accomodate oysters in a body-down configuration. Two axles145 extend across the conveyor below the conveyor chains. Pulleys 146are carried at the center of the axles and a belt 147 connects thepulleys. A front flight 113' includes a horizontal tray portion 115'having an oyster-carrying hole 148 in the center of the tray. The holeis large enough to permit the body of an oyster to extend a substantialdistance through the hole yet not so large as to permit the oyster topass all the way through the hole. Alternatively, the horizontal trayportion could be formed by two crossbars with a slot between the bars ofa width the same as the diameter of hole 148. As the front flight nearsthe bridge barrier, the oyster body protruding through the hole willengage the lower belt 147 and be forced against the upper belts 138.Bridge barrier 75" is positioned a set distance down from belts 138 andis adjusted so that the oyster strikes the barrier at the joint betweenthe oyster half shells, thereby opening the oyster in the same manner asthe component of FIGS. 25 to 27.

After the oyster shells have been sheared apart in the manner statedabove, the meat will be exposed for removal from one of the shells,usually the body shell, in any desired manner either manually ormechanically.

I claim:
 1. The method of opening an oyster which comprises supportingthe oyster on a support member engaging a central portion of theexterior of one half shell of the oyster, engaging an edge portion ofthe exterior of one half shell of the oyster with a first force-applyingmember connected to the support member, and driving the support memberand the first force-applying member relatively toward a secondforce-applying member to engage the second force-applying member againstthe edge portion of the oyster half shell not engaged by the firstforce-applying member which latter edge portion is generally oppositethe shell edge portion engaged by the first force-applying member forapplying shearing force to the oyster for separating the oyster halfshells.
 2. The method defined in claim 1, including supporting theoyster on a generally horizontally extending support member such thatthe oyster rests on the support member with the plane between the oysterhalf shells extending generally horizontal.
 3. The method defined inclaim 1, including supporting the oyster on the support member byengaging the oyster between the support member and a hold-down memberthat engages a central portion of the exterior of the oyster half shellnot engaged by the support member.
 4. The method defined in claim 1,including applying the shearing force to the oyster without insertion ofa sharp pointed member between the oyster half shells.
 5. The methoddefined in claim 1, 2, 3 or 4, including driving the secondforce-applying member abruptly against the edge portion of the oysterfor applying an abrupt shearing jolt to the oyster.